The aim of this systematic review was to examine the effects of a lingual arch on mandibular arch dimensions when it is used as a space maintainer.
PubMed, Medline, Lilacs, Cochrane Central, and Cochrane Database of Systematic Reviews were surveyed for articles published between January 1980 and January 2009. Inclusion criteria were human subjects, prospective or retrospective method, effect of the lingual arch used as space maintainer in the mandibular arch, and publication in English.
Of the 262 studies identified in the search, only 2 met the final inclusion criteria.
The results showed that the lingual arch is effective for controlling mesial movement of molars and lingual tipping of incisors.
If I have told 1 resident, I’ve told them all, “I could not practice without the lingual arch.” I am shocked when I hear of clinicians who never use this appliance, and I am not shy about asking, “How better to maintain arch length when the last 2 or 3 deciduous molars are ready to exfoliate? Is there any better way to save the e-space and prevent lingual tipping of the mandibular permanent incisors during the late mixed dentition stage of tooth eruption?” But can I prove that a fixed lingual arch really works? What evidence do I have? The aim of this study was to conduct a systematic review to evaluate the effects of the lingual arch as a space maintainer of mandibular arch dimensions.
To identify all studies reporting the effect of the lingual arch as a space maintainer, a computer search was conducted of PubMed, Medline, Lilacs, Cochrane Central, and Cochrane Database of Systematic Reviews from January 1980 to January 2009. The terms used for the literature search were “lingual arch, space maint, anchor, arch length, arch width, incisor crowding, and orthodontics.” The inclusion criteria included prospective and retrospective human studies. Animal studies, case reports, and case series or studies that did not report arch dimensions were excluded. The simultaneous use of other fixed appliances was also a reason for exclusion. Only 6 articles of the 262 initially identified fulfilled all selection criteria. After further evaluation of these articles, only 2 remained. Detailed arch dimensional changes were recorded in both studies and compared with untreated control groups.
These results support the use of lingual arches for preserving arch length. Placing a fixed mandibular arch during the early transitional dentition will restrict mesial migration and use of the leeway space. It is also an important way to resolve marginal crowding, by controlling space use in the mandibular arch with activation of the lingual arch attached to the first molars, which might even cause a slight increase in the total arch length. As logical as this might sound, both studies examined were retrospective; thus, the opportunity for bias was considered moderate. Randomized controlled trials are still needed to validate this treatment regimen with greater strength.
Q & A
Turpin: Do you have any plans to conduct a randomized controlled trial to verify these findings? Is it possible that this study design would not be ethical now that we have the results of your systematic review?
Viglianisi: Data have emerged from this review to show that a few studies analyzed the effects of the lingual arch, although this device has been known for many years. The 2 studies included in the review were well designed. The only thing that I think could improve them, giving greater weight to the results, would have been randomization of the samples. It might increase the likelihood that other variables, not considered in the study design, were distributed uniformly in the experimental and control groups. Thus, any differences between the 2 groups could be attributed to treatment with the lingual arch. Randomization needs to be supported by a precise statistical analysis that takes into account the possibility that the groups are not perfectly identical and the differences are not due to chance imbalances between the groups; the results should be quantified.
Turpin: Did you find that improper fabrication of lingual arches can result in failure and loss of arch length?
Viglianisi: Improper fabrication can certainly affect maintenance of the space. In addition to not keeping the space, there is a risk that the incisors might undergo excessive tipping in the vestibular or lingual direction. Furthermore, if the bands are not parallel, they could tip the molars.
Turpin: Have you considered comparing the results of lingual arches with those of properly timed lip bumpers?
Viglianisi: I’d like to make a comparative study between the lingual arch and the lip bumper in light of this review and also the data in the literature on the lip bumper that show how it can increase arch width, procline the incisors, and distalize and distally tip the molars. I want to focus on the time and the characteristics that allow optimal use of 1 device rather than another, and whether their effects can overlap.